Carrier-wave telephone system



l "i v y April 10, 1 928. 1,665,904

- c. A. BODDIE CARRIER WAVE TELEPHONE SYSTEM Filed Aug. 18. 1923 wnusssss; mvsmon I Clarence 4. Bode/la BY flay Mu Patented Apr. 10, 1928.

CLARENCE A. BODDIE, OF WILKINSBURG, PENNSYLVANIA, ASSIGNOR TO WESTING- HOUSE ELECTRIC & MANUFACTURING COMPANY, A

VANIA.

CORPORATION OF PENNSYL- CABRIER-WAVE TELEPHONE SYSTEM.

Application filed August 18, 1923.

. transferring carrier-wave frequency currents sion lines, means along transmission devices in the lines.

Broadly speaking, the object of my invention is to provide a path from an end of one transmission line to the adjacent end of anlines past sectionalizing other transmission line, through which the carrier current can pass when the respective ends of the transmission line are separated by such a distance that ordinary inductive and capacity effects between them will not adequately convey the energy from one line to the other.

More specifically, my invention provides a conductive device in inductive and capacitive relation to the end portions of transmisdevice is made resonant to the currents which are to be transferred and means for draining out undesired inductive effects.

In the use of carrier-current signaling methods over line wire networks, it has been found that the carrier current will follow a single line quite readily and that a substantial amount of energy will reach the distant end of the line. It has been found, also, that the presence of sectionalizing equipment, such as transformers, switches, lightning arresters and similar apparatus, such as may lbs used in the operation of a transmission ine, increased resistance to the passage of carriercurrent frequency energy. The opposition to 7 the passage of this current is seemingly due to the presence of masses of iron in the sectionalizing equipment and the presence of large inductive and capacitive factors.

In many installations, it is desired to energize a transmission network from some given point and have energy transferred to all parts of the network. If the network contains a substantial number of sectionalizing devices, this result is difiicult to secure and it may require an excessive amount of power .at the input point to reach all parts of the network. 7

My invention provides means whereby the resistance of the carrier-wave current enerinterposed by sectionalizing devices, may reduced and energy may readily be transferred between sections of thc network.

Other objects and structural details of 'mission line 1 that is whereby this conductive causes the line to offer a substantially b Serial No. 658,040.

my invention will be apparent from the following description and claims when read in connection with the accompanying drawing, wherein:

Figure 1 is a diagrammatic View of a transformer substation interposed between two sections of a high tension transmission line over which it may be desired to transfer carrier-current energy for signaling purposes, and in which is shown one form of my invention.

Fig. 2 is a similar view of an equivalent circuit,

Fig. 3 shows an equivalent circuit having a different type of capacitive coupling.

Referring to Fig. 1, a high tension transsupported upon a pole structure 2, is connected to a device 3 which may be a transformer, a sectionalizing switch, or other apparatus. The sectionalizing apparatus 3 is, in turn, connected to a second transmission line 4 mounted upon another pole structure 5. Parallel with the line 1 is supported a conductor 6 and parallel with the line 4 is mounted a conductor 7. Conductors 6 and 7 are joined at point 8 to a third conductor 9 which leads to a tuning coil 11.. The conductors 6 and 7 may be relatively short, and may conveniently span the distance from one pole to the next. A desirable length is a few hundred feet. Tuning coil 11 is connected to ground at 12 y a conductor 14.

In Fig. 2, a conductor 6 and a conductor are provided, as before, in inductive relation with two'transmission lines. Conductor 6 is connected to a tuning coil 15 and conductor 7 is connected to a tuning coil 16. Both coils are connected to ground at 12 by lead wires 17 and 18. Coils 15 and 16 are placed in inductive relation.

In Fig. 3, another means of obtaining oapac-itive coupling to the line conductors is shown. In this figure are shown lead-in bushings 22 and 23 to a sectionalizing device 27 These bushings consist of, insulating material surrounding a main conductor and separating it from the casing 28 of the sectionalizing device. In the bodies of the bushings are provided additional conductors 21 and 26 separated from the main conductors by part of the body insulating material of the bushings and forming, with the main conductors, condensers or electrical capacitransfer tances. Conductors 21 and 26 are also insu lated from the casing 28. These several capacitances respectively connected at the ends of the two line sections are also connected, respectively, to the ends of coil 24 whose middle point is connected to ground at 12 by a conductor 25. y

In the operation of the system of Figs. 1 and 2, a carrier current frequency impressed upon the transmission line will be trans ferred by capacitive coupling from the transmission line wire to the conductor 6 paralleling it, and in the case of the system of Fig. 3, by capacitive coupling to the conductor within the bushing. The circuit con1- prising conductors 6 and. 9, tuning coil 11, lead wire 14 and the ground 12 oscillates at the frequency of the incoming signal energy. This condition of oscillation is markedly favored by carefully tuning the coil 11. In the circuit comprising elements 6, 9, 11, 14 and the ground in oscillation, the variations in potential of point 8 will set in oscillation the similar circuit comprising elements 7, 9,

11, 14 and the ground. In this circuit also,

oscillation is markedly favored by careful tunin of the circuit. Energy will then be transferred from conductor 7 to transmission line 4 which will convey it towards the desired reception point. In the case of the arrangement shown in Fig. 2, the circuit comprising elements 6, 15, 18 and the ground may be set in oscillation by incoming carrier wave energy. Coils 15 and 16 being then in inductive relation, energy will be transferred to the circuit comprising elements 7, 16, 17, 18 and the ground from which it is transferred to another portion of the transmission lines.

In the case of the system of Fig. 3, the condenser portion, which is made a part of the insulating bushing used in the construction of the sectionalizlng device, absorbs energy from the incoming line-by capacitive coupl ng. This energy sets into oscillation the circuit comprising condenser 21, half of 0011 24, ground lead 25 and ground 12. En ergy is then transferred as in the case of Fig. 2 from one half of coil 22 to the other half, setting into oscillation a circuit comprising elements 26, the other half of coil 24, groundlead 25 and the ground 12. From this system, energy is transferred to a sec-- ond portion of the transmission line network through capacitive coupling between the conductor in the body of bushing 23, and the line conductor in the same bushing. It will be obvious that these oscillatory circuits will absorb amajor portion of the oscillatory energy arriving at the end of one transmission line, oscillate strongly to that energy, and a major portion of it to another portion of the transmission line, which is the object sought.

The fact that this device comprises two tuned circuits gives a' selective action which transmits a certain frequency more readily than other frequencies, thereby reducing possibilities of interference from currents of other frequencies. In this way it serves to drain out any power frequency disturbances Which might otherwise influence the receiving apparatus.

While I have shown only three embodiments of my invention in the accompanying drawings, it is capable of still further modifications and changes without departing from the spirit and scope thereof and it is desired, therefore, that only such limitations shall be imposed thereon as are indicated in the prior art or in the appended claims.

I claim as my invention:

1. A carrier-frequency system for the transfer of signals over lines, comprising a line, sectionalizing apparatus in' said line, and a transfer means for carrying carrierfrequency energy past said sectionalizing apparatus, said transfer means comprising one or more wires coupled to said line, and a tuned drain-coil system connecting said wires to earth. 2. In combination, line conductors and a transfer means for carrier-frequency currents serving to transfer said carrier frequency currents from one line conductor to another, said means comprising conductors coupled to said line conductors, and a tuned drain-coil system connecting said conductors to earth.

3. The combination with a -plurality of sections of line wires, a carrier-current system for the transfer of signals over said line and a conductor system for conveying the carrier frequency from section to section of said line wires, said conductor system comprising a plurality of conductors coupled to the sections of said line wires, and a tuned drain-coil system connected between said conductors and the earth.

4. The method of conveying carrier-frequency currents around a sectionalizing device in a line which consists in transferring them from one section thereof to an auxiliary conductor by a coupling action, conveying them to another auxiliary conductor, drainingaway extraneous frequencies during said conveyance and transferring the carrier-frequency currents from said second auxiliary conductor to the next section of the line by coupling action.

5. A transmission line having a discontinuous portion, and energized with carrier frequency energy, a conductor system in inductive relation to said transmission line, said conductor system being a path for said carrier and a tuned ground connection to said conductor systems. I

6. A transmission line having a discontinuous. portion, means for supplying low frequency energy thereto, means for supplying carrier frequency to said line for the transmission of signals, and a conductor system for carrying said carrier frequency energy past said discontinuous portion, said conductor system comprising a tuned ground connection.

7. The method of conveying carrier frequency signal energy past a discontinuous portion in a transmission line which consists in inductively transferring said energy from said trasmission line on one side of said discontinuous portion to an oscillatory cir- 'cuit, excluding extraneous frequencies by the tuning of said oscillatory circuit, transferring said energy from said oscillatory circuit to a second oscillatory circuit, further excluding extraneous frequencies by the tuning of said second oscillatory circuit and inductively transferring said carrier frequency energy therefrom to said transmission line on the other side of said discontinuous ortion.

8. n combination, a transmission line having a plurality of sections and controlling apparatus therebetween, conducting memers adjacent to said line sections and forming capacitive devices therewith, and a connection therebetween comprising tuning and grounding means.

In testimony whereof, I have hereunto subscribed my name this 13th day of August, 1923.

CLARENCE A. BODDIE. 

